Mr. Oliva Castillo is an alleged top leader of the Zetas drug group, and more significant, the alleged mastermind of the arson attack that killed 52 people in a casino in August, most of them middle-aged women.

The casino attack, in the northern city of Monterrey, is largely considered to be one of the most horrific acts of violence in Mexico, since Mexican President Felipe Calderon took office in 2006 and announced that federal forces would fight drug traffickers.

"People despise the Zetas because they are very violent. Other organizations, their only business is drugs. Not kidnapping or extortion. If you have to make a choice, if you can say there are 'good criminals,' the Zetas are considered the bad ones," says Javier Oliva Posada, a drug expert at the National Autonomous University of Mexico. "When the criminal organizations attack the civic population, they are lost."

Oliva Castillo was captured at a safe house in Saltillo on Wednesday, according to the Defense ministry, after a firefight between gunmen attempting to rescue their leader and soldiers.

Oliva Castillo was presented to the news media Thursday in a red, white, and black checkered buttondown and an orange fluorescent vest similar to what road workers wear.

He is considered the No. 3 within the organization. The two leaders above him are still at large.

Former special forces

The arrest is a blow to the Zetas, who are former special forces who deserted. They were the armed wing of the Gulf Cartel until those two groups splintered in 2010. They have amassed foes in the past two years. A group called specifically the “Kill Zetas” has emerged to do exactly what they say – a feud now playing out in Veracruz state.

Oliva Castillo's capture is also good news for Mexicans weary of their tactics, which, instead of focusing solely on drug trafficking, include extortion and kidnapping.

Most of all, his arrest will be hailed because of his involvement in the Casino Royale tragedy. About a dozen suspects have been arrested so far. But officials say it is he who ordered a colleague to set fire to the casino (believed itself to be a case of extortion). He was reportedly captured after an anonymous source alerted officials to his activities and sent a photo.